According to tradition, Ismāʿīl was descended from an imam. His father, leader of a Shīʿite group known as the Kizilbash (“Red Heads”), died in battle against the Sunnis when Ismāʿīl was only a year old. Fearful that the Sunnis, the majority sect, would wipe out the entire family, Shīʿite supporters kept family members hidden for a number of years.

Ismāʿīl emerged at the age of 14 to take his father’s position as head of the Kizilbash. He quickly established a base of power in northwestern Iran, and in 1501 he took the city of Tabrīz and proclaimed himself shah. In a succession of swift conquests he brought all of modern Iran and portions of present-day Iraq and Turkey under his rule.

In 1510 Ismāʿīl moved against the Sunni Uzbek tribes in what is now Uzbekistan. By skillful use of ambush, Ismāʿīl was able to defeat a 28,000-man Uzbek force with only 17,000 Iranians in a battle near the city of Marv. Muḥammad Shaybānī, leader of the Uzbeks, was killed trying to escape after the battle, and Ismāʿīl had his skull made into a jewelled drinking goblet.

The Shīʿite sect of Islam was proclaimed by Ismāʿīl to be the established religion. The fact that much of the population considered him a Muslim saint as well as shah facilitated the process of conversion. Ismāʿīl’s action provoked the Ottoman Turks. Religious friction grew after the Turkish ruler Sultan Selim I executed large numbers of his Shīʿite subjects as heretics and potential spies. He then wrote Ismāʿīl a series of belligerent letters. Ismāʿīl replied that he had no wish for war, adding that he thought the letters had been written under the influence of opium; he also sent Selim’s royal secretary a box of the drug. Selim was an opium user, and the gesture hit home.

In 1514 the Ottomans, with highly trained professional troops armed with muskets and artillery, invaded northwest Iran. Ismāʿīl rushed from his campaigns in Central Asia to oppose the threat to his capital at Tabrīz. In a hard-fought battle, Selim and a force of 120,000 troops defeated Ismāʿīl and his army of 70,000. Ismāʿīl was wounded and nearly captured as he tried to rally troops. The Ottomans then took Tabrīz without opposition. A mutiny among his troops, however, forced Selim to withdraw, giving Ismāʿīl time to recover his strength.

The warfare continued as a series of border skirmishes for a number of years, but Ismāʿīl remained strong enough to prevent further inroads by the Ottomans. In 1517 Ismāʿīl moved northwest, subduing the Sunni tribes in what is now Georgia. The basic conflict between the Shīʿite empire Ismāʿīl had founded and the Sunnī Ottomans in the west and the Sunni Uzbek tribes in the east continued for more than a century. Ismāʿīl died at the age of 36, but the Ṣafavid dynasty ruled Iran for two centuries, until 1722.